MCP-1 expression in endotoxin-induced uveitis.

Purpose: Monocyte chemoattractant protein (MCP)-1 (CCL-2) is a chemokine with chemoattractant properties for monocytes, memory T cells, natural killer cells, mast cells, and basophils. To delineate the role played by MCP-1 in acute anterior uveitis, a common ocular inflammation, MCP-1(-/-) mice and wild-type matched control mice were analyzed for the development of endotoxin-induced uveitis (EIU) in response to subcutaneous injection of a sublethal dose of lipopolysaccharide (LPS).

Methods: EIU was induced in MCP-1(-/-) and wild-type control mice by a single subcutaneous injection of Salmonella typhimurium LPS endotoxin at day 0. Alternatively, MCP-1(-/-) mice were injected subcutaneously with LPS plus recombinant MCP-1 at day 0 and with recombinant MCP-1 6 hours later. Mice were killed at day 1 or 3 after injection. Serum levels of IL-1alpha, IL-1beta, IL-6, IFN-gamma, TNF-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage inflammatory protein (MIP)-1alpha, MIP-2, regulated on activation normal T-cell expressed and secreted (RANTES), and MCP-1 were determined by ELISA. Eyes were collected and analyzed histologically and by RT-PCR for MCP-1, IFN-gamma, IL-6, TNF-alpha, beta-actin, MCP-5, RANTES, KC, inflammatory protein (IP)-10, and toll-like receptor (TLR)-4.

Results: EIU was strongly reduced in MCP-1(-/-) mice compared with wild-type control mice. The number of ocular inflammatory cells was significantly reduced. Moreover, intraocular IFN-gamma transcription was increased. EIU was induced in MCP-1(-/-) mice by co-administration of recombinant rat MCP-1 and LPS.

Conclusions: Data indicate that MCP-1 plays a crucial role in the induction of EIU. MCP-1 may be a new therapeutic strategy for acute anterior uveitis.